1. Field of the Invention
The present invention relates to a fitting for connecting two components. More particularly, this invention relates to an explosion proof fitting to join two electrical components, such as electrical conduits.
2. Description of the Related Art
In the workplace, it is often necessary to run electrical conductors or wires in hazardous environments. Hazards are created by the possible presence of ignitable quantities of flammable liquids, gases, vapors, combustible dusts, or ignitable fibers. Examples of hazardous work environments include, but are not limited to, locations where volatile flammable liquids are transferred from one container to another; interiors of spray booths; in the vicinity of spray painting operations where volatile flammable solvents are used; locations where dangerous concentrations of suspended dust are likely, such as in grain elevators; and gasoline fueling stations.
Hazardous locations require specially designed electrical equipment to protect against increased fire potential. To run the electrical conductors or wires through these hazardous workplaces, the conductors or wires are encased in electrical conduits. Among other things, the conduit prevents an electrical short, arcing, or intense heat from escaping into the flammable atmosphere causing a fire. Further, fittings connecting these electrical conduits in a hazardous workplace must be xe2x80x9cexplosion proof.xe2x80x9d Multiple standardsxe2x80x94such as in Article 501, Section 501-5 of the National Electric Code; National Electrical Manufacturers Association (xe2x80x9cNEMAxe2x80x9d) ICS 6-1993 (entitled xe2x80x9cEnclosuresxe2x80x9d) and NEMA Classes 4-13; American National Standards Institute (xe2x80x9cANSIxe2x80x9d); and UNDERWRITER""S LABORATORIES INC., UL 886 and 1002xe2x80x94govern explosion proof electrical components for use in hazardous environments. By utilizing properly installed and maintained explosion proof equipment, intense heat or an arc inside the electrical conduits or components will not ignite the dangerous atmosphere surrounding them.
Many of the components in an electrical system, such as solenoids, require routine periodic maintenance. As such, it is desired that a fitting be quickly, simply; and easily installed and removed, but still maintain the explosion proof connection.
Further, some of the conduits in an electrical system may be permanently mounted at a location. Therefore, it may not be possible to rotate one conduit to attach it to the fitting or to another conduit. Thus, there is a need for an explosion proof fitting that is capable of quickly and easily attaching two conduits, even when one conduit or both conduits cannot rotate. This is especially true in electrical systems having components requiring periodic maintenance.
U.S. Pat. No. 3,979,814 to Lajoie et al., entitled xe2x80x9cPipe Fitting Device,xe2x80x9d describes a clamp for quickly attaching one conduit to another. Further, U.S. Pat. No. 4,018,462 to Saka, entitled xe2x80x9cPipe Fitting,xe2x80x9d describes sealing one conduit onto another by deforming one portion of a conduit. However, these simple and relatively quick methods for connecting two conduits are inappropriate for use in a hazardous environment as they may not seal the conduits sufficiently to prevent a flame caused by an arc from reaching the surrounding atmosphere.
U.S. Pat. No. 4,840,194 to Berry describes a sealing fitting having four sub-elements to connect two electrical conduits. The Berry fitting is sealed, and thus made explosion proof, by sealing the fittings with damming material. However, the inclusion of the damming material has been found to be an imprecise art, especially in light of the numerous voids which must be sealed as described in Berry. Further, re-use of the Berry fitting requires the fitting to be deconstructed and cleaned before re-use. It has been found that this type of arrangement may increase the cost and time to complete routine maintenance of the connected components. Finally, aligning the four different fitting components is not easy to perform in the field, thus increasing the time and cost of performing routine maintenance on an electrical system.
In one embodiment of the present invention, a fitting for connecting a first component to a second component is provided. The fitting comprises a bushing having a threaded end for threadedly engaging the first component, and a smooth male end having an outer diameter. An adapter is described as having a threaded end for threadedly engaging the second component, and a female collar end. The adapter has an inside diameter and receives the smooth male end of the bushing. The adapter also has a locking mechanism to connect the adapter to the bushing when the smooth male end of the bushing is inserted into the adapter. The outer diameter of the bushing is in close communication with the inner diameter of the adapter to define a flame path to produce an explosion proof fitting. In some embodiments, the locking mechanism further comprises a groove. The grove is formed along an outer perimeter of the bushing. A screw having a tip may be radially inserted through the collar of the adapter. The tip of the screw mates with the groove of the bushing to allow the adapter to rotate about the bushing. In some embodiments, the tip of the screw is screwed into to the groove to rigidly attach the adapter to the bushing.
In other embodiments, a method of connecting a first component to a second component is described. The method comprises providing a fitting for connecting a first component to a second component, the fitting having the features described above. The method includes rotating the bushing to threadedly engage the fitting to the first component. The method also includes rotating the adapter to threadedly engage the fitting to the second component.
In other aspects, a fitting is described for connecting a first component to a second component. The fitting comprise a bushing having a threaded end for threadedly engaging the first component and a smooth male end having an outer diameter. An adapter is described having a threaded end for threadedly engaging the second component. The adapter also has a female collar end and an inside diameter. The adapter receives the smooth male end of the bushing. The adapter also has a locking mechanism to connect the adapter to the bushing when the smooth male end of the bushing is inserted into the adapter.